Various interfaces and designs have been developed for an operation input unit of a portable electronic apparatus. For example, Japanese Patent Application Laid Open No. 2003-280792 discloses a portable electronic apparatus with a rotary dial input device that moves a cursor displayed on a display unit according to the rotation amount of the rotary dial input device.
However, since the technique disclosed in the Japanese Patent Application Laid Open No. 2003-280792 employs “rotary dial” rotated physically and mechanically, there are troubles or errors caused by mechanical abrasion, therefore maintenance of the operation input unit is necessary, and the durable period is short.
In order to solve above problems, for example, techniques employing touch sensor elements, which are not operated by physical and mechanical rotations, in an operation unit have been suggested in Japanese Patent Application Laid Open Nos. 2005-522797 and 2004-311196. These techniques arrange a plurality of touch sensors annularly to detect contacts, and when continuous contacts are detected, it determines there is a movement instruction of a cursor and moves the cursor according to the movement of detected contact points.
On the other hand, application programs (hereinafter, it is referred to as an application simply) executed in recent cellular phones have been diversified, and therefore various operations of a user are required.
However, techniques disclosed in Japanese Patent Application Laid Open Nos. 2005-522797 and 2004-311196 are limited to a process for detecting in which direction the plurality of touch sensors arranged annularly are contact-operated in a forward direction or a reverse direction, and moving a cursor in one direction or the other direction among two directions according to the detected direction. With these techniques, it is difficult to deal with various inputs by a user according to each application. Therefore, a mobile electronic apparatus only having such a touch sensor is not sufficient for a user interface that controls various operations of applications.
In order to solve the problem, it is considered to provide another user interface to having a different process management system on a housing of a portable electronic apparatus, as well as a sensor element group detecting two-directional movement. However, in a portable electronic apparatus, a surface area of a housing on which the sensor element group and another user interface are mounted is limited, and therefore it has to employ a sensor element group and another user interface having small sizes, respectively.
However, employing the small sensor element group and small another user interface mounted on the housing of the portable electronic apparatus compels a user to do an input operation with a small movement of a finger. Thus, the user is likely to make mistakes and the sensor element group cannot determine an input as user's intention.